Soiling or coking can occur particularly in the region of the burner nozzles while burners are being operated by means of heating oil. The burner will consequently cease being able to perform at fill capacity. Excessive soiling or coking can furthermore damage burner components. A drop in performance due to soiling or coking of the burner is detrimental in the case particularly of gas turbines because the gas turbine's overall performance and emission values are negatively affected thereby.
When impurities are detected in gas turbine burners, the burner nozzles are at present broken through by hand. Blow-out runs then have to be carried out on the gas turbine during which any dirt residues will be blown out of the nozzles.
Furthermore, gas turbine burners are frequently provided with annular spaces that duct the heating oil from a central heating oil supply line to fuel nozzles arranged annularly around a central burner part. The annular space sited inside the burner cannot be cleaned using the cited means. If the burner's operational restrictions cannot be eliminated by breaking through the nozzles, the nozzles will have to be removed. Only then can the annular space be cleaned, though that can be done only to a limited extent. The removed nozzles can then be cleaned in a cleaning bath as is described in, for example, EP 0 636 767 A1. More extensive cleaning will require complete dismantling of the burner.
An apparatus for washing an air supply channel in a gas turbine burner is described in EP 1 452 802 A1. The apparatus includes a nozzle body having a discharge end in which is located an annular nozzle assembly that can be arranged opposite the likewise annular air supply channel. By spraying a fluid into the air supply channel through the annular nozzle assembly the latter can be cleaned of residues. For being secured to the burner the apparatus furthermore includes a rod that projects beyond the nozzle body's discharge end and has an annular flange arranged at a distance from the nozzle body. For performing a washing operation from inside the combustion chamber the nozzle body is applied against the burner's air supply channel and the rod ducted through the burner as far as its other end. The assembly is then fixed into position by means of a tensioning bolt by tensioning the nozzle body and flange against mutually opposite ends of the burner.
A mobile flushing unit is described in EP 1 574 675 A2. It includes flexible hoses requiring to be secured to opposite ends of a workpiece. Compressed air and a cleaning fluid can then be pumped through the flexible hoses and the workpiece located between them.
U.S. Pat. No. 4,995,915 discloses a system for cleaning dirty gas firing nozzles in gas turbines, in which system a cleaning chemical is added to the gas while the gas turbine is operating.